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Messages - alexxw24

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1
General / Re: pixel rain
« on: 2019 December 15 14:33:51 »
Strange pattern.
Did you used darkframe scaling? The subframes are dithered?

Try to stack the subframes uncalibrated, then only dark calibrated and so one to find the source of the pattern.

Please send some feedback as curious to get to know where it comes from.

2
General / Re: Synthetic Flat for DSLR ?
« on: 2019 December 01 12:53:13 »
Dear,

I m sure you will be able to correct this edge vignetting by using DynamicBackgroundExtraction or AutomaticBackgroudExtraction, no need for synthetic flat.

Kind regards,
Alex

3
General / Re: M76 Narrowband and LRGB Data
« on: 2019 November 24 09:03:30 »
Hi Steve,

giving the extensive amount of data with 93 hrs with an 12,5” scope I could imagine much more galactic dust and faint Ha or OIII clouds to be visible in the image. Maybe some enhancement of large structure / layers could help.

Anyway fantastic resolution and smooth processing.

Cheers,
Alex

4
Okay, thanks.

Yes, had best results with scale 1 and drop shrink 1 as well.

5
Hi everyone,

e.g. Juan mentioning CFA DrizzleIntegration as the recommended way for integrating DSLR/OSC data some time ago (see underneath).
I'm usually working with a mono-CCD but have some DSLR widefields from earlier this year to process ahead of me.

I want to understand the background, why CFA Drizzle is supposed to be better / recommended, well dithered and larger number of sub frames assumed.

The positive effect on undersamples subs I am aware off but what makes it with the bayer matrix, better color interpolation?

Thanks for your thoughts,
Alex


Quote
I am under the impression that AHD is superior to VNG.

Why? Yes, we can implement more CFA interpolation algorithms in the Debayer tool. However, this is not a priority task for the following reason: In current versions of PixInsight, CFA interpolation with the Debayer tool is intended exclusively for generation of temporary working images, required as input for StarAlignment. The only recommended way to generate integrated color images from CFA raw data, be it data acquired with digital cameras or single-shot CCD cameras, is DrizzleIntegration (i.e., CFA drizzle, AKA Bayer drizzle). The only exception may be if you have just a marginal number of raw frames, where drizzle may not be applicable.
....

6
General / Re: calculating real bit depth / quantization
« on: 2018 September 26 08:30:16 »
Hi Enzo,

this is what I was looking for!

Thanks a lot,
Alex

7
General / calculating real bit depth / quantization
« on: 2018 September 25 11:45:03 »
Dear members,

any idea how the real bit depth of a sub frame could be calculated using e.g. pixel math or a self-written script?

In detail, I want to determinate the absolute number of different values used in a mono or RGB subframe (per channel)
1) as strongly believe to not always have to use 32bit floating for saving an image
2) as we have a nice dicussion in our local astro community regarding gain settings.

For example a 16bit image can store 65535 values but there are only 30587 in the subframe.
In the HDR composition process  for example an initial quantization is given out at the console, what's the calculation behind?

Thanks in advance and best regards,
Alex

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